Roger A. Falconer

Cardiff University | CU · School of Engineering

This paper presents a robust cost-effective framework for assessment of coastal-fluvial flooding due to compound action of multivariate dependent drivers. The methodology is an 8-step process that links statistical and hydrodynamic models to determine probabilities of multiple-driver flood events and associated hazards. The method involves individu...

With more than half the global population living closer than 3 km to surface freshwater (Kummu et al.,2011), shallow water bodies such as rivers, canals and estuaries can be a valuable source of sustainable energy for local communities. While most contemporary research has focused on tidal currents and lift-based axial flow turbines (Laws and Epps,...

In this study fecal bacteria processes have been investigated using the EFDC 2D/3D model, based on local refinements using an orthogonal curvilinear grid system and with the model being applied to Ribble river basin, through the estuary, and into the Fylde Coast. The input fluxes from numerous minor rivers and streams within the basin were solved u...

The article introduces some of the general challenges of global water security (in the context of the availability of good quality water) and highlights the likely global impact of climate change, increasing pollution and population growth on water resources, including flooding and droughts, as outlined in recent studies. The nexus between water, f...

The topic of Global Water Security (GWS) came to the foreground during the various World Water Forum events taking place in the years 2006 (WWF Mexico), 2009 (WWF Istanbul), and 2012 (WWF Marseille). Based on the outcomes of these events, UN-WATER drafted a document and working definition, as illustrated in Figure 1. This definition includes all as...

Street inlets play a key role in intercepting surface runoff into underground drainage systems, which can reduce the hazard degree during urban flood events. An accurate calculation of the discharge capacity of street inlets is vitally important in numerically modelling urban floods and managing flood resilience. A series of laboratory experiments...

In order to accurately simulate the whole urban flooding processes and assess the flood risks to people and vehicles in floodwaters, a 2D-surface and a 1D-sewer integrated hydrodynamic model was proposed in this study, with the module of flood risk assessment of people and vehicles being included. The proposed model was firstly validated by a dual-...

As a key component of global change, dam‐induced sediment reduction occurs in large rivers worldwide, which has profound implications on the fluvial systems. However, the systematic change of suspended sediment concentration (SSC) and its dynamic processes are not well known. We summarize typical SSC changes and propose a new sediment modeling fram...

An accurate assessment of the hydro-environmental impacts of tidal range energy schemes, where the performance of the scheme has an impact on the marine environment and ecology, is crucial in optimising the design and development of such schemes. A proposal for a new coastally-attached impoundment, namely West Somerset Lagoon, has been investigated...

In this paper, a large-eddy simulation study of turbulent free surface flow over a natural rough bed is presented. A three-dimensional multiphase flow model is employed to study the roughness effects on the turbulence properties and free surface dynamics. The governing equations have been discretized using the finite volume method, with the Cartesi...

The Water Informatics in Science and Engineering Centre for Doctoral Training (WISE CDT) offers a postgraduate programme that fosters enhanced levels of innovation and collaboration by training a cohort of engineers and scientists at the boundary of water informatics, science and engineering. The WISE CDT was established in 2014 with funding from t...

One of the key aspects of Tidal Range Schemes globally is identifying the most appropriate site and the optimised design and operation of the scheme, to maximise societal needs and the benefits from electricity generation. Variations in the design parameters of Tidal Range Schemes for electricity generation could therefore lead to a very large numb...

In recent years, society has become more aware and concerned with the environmental and human health impacts of population growth and urbanisation. In response, a number of legislative measures have been introduced within Europe (and globally), which have sparked much cross-disciplinary research aimed at predicting and quantifying these impacts, an...

Accurate prediction of flood inundation processes in urban areas is challenging, due to the complexity of street layouts and the variety of infrastructures. In this study, based on a laboratory model of urban flooding with a sewer system underneath, a series of laboratory experiments were conducted to investigate the influences of different street...

Floods have caused severe destruction and affected communities in different ways throughout history. Flood events are being exacerbated by climate change and hence it is increasingly necessary to have a more accurate understanding of various aspects of flood hazard, particularly for pedestrians. The focus of this study is therefore to investigate d...

The Water Informatics in Science and Engineering Centre for Doctoral Training (WISE CDT) offers a postgraduate programme that fosters enhanced levels of innovation and collaboration by training a cohort of engineers and scientists at the boundary of water informatics, science and engineering. The WISE CDT was established in 2014 with funding from t...

This paper presents a study of two transport timescales (TTS), i.e., the residence time and exposure time, of a hyper-tidal estuary using a widely used numerical model. The numerical model was calibrated against field measured data for various tidal conditions. The model simulated current speeds and directions generally agreed well with the field d...

This chapter introduces the opportunities for designing and developing coastal reservoirs for urban regeneration and renewable energy generation. The case for using coastal reservoirs for such applications is first presented, followed by an outline of the governing equations and modelling approaches used in the planning of such reservoirs. Two case...

Coastal reservoirs

Coastal and riverine waters can be impaired in many ways; one important way is pathogenic microbe contamination of water used for drinking, aquaculture and human recreation. Faecal Indicator Organisms (FIOs), which indicate the presence of faecal pathogens, have been used to define the legal compliance status of bathing waters in EU Directive 2006/...

Extreme flood events are becoming more frequent and challenging due to climate change. Key objectives of this study are to evaluate different criteria used in assessing the hazard to people during flood events and, once determined, the most suitable method is then used to assess the hazard and the safest route(s) for evacuation during a flood event...

Tidal flow can generate unsteady wakes, large eddies, and recirculation zones in the lee or around complex natural and artificial obstructions, such as islands, headlands, or harbours. It is essential to understand the flow patterns around such structures given the potential impacts they can have on sedimentation, the marine environment, ecology, a...

Understanding the impact of various hydraulic structures, such as coastal reservoirs and tidal range impoundments, has been one of the key challenges of hydro–environmental engineering in recent years. Over the last half-century, several proposals for tidal range schemes in the UK have been scrutinised and then abandoned due to the uncertainty over...

Tidal lagoon has gained further interest in recent years because of the increasing demand for renewable energy and their potential in providing other benefits, such as coastal protection. Accurate modelling of such schemes is essential to predict their operation, hydrodynamic and hydro-environmental processes, and power output. In this study, Telem...

A theoretically based relationship for the Darcy–Weisbach friction factor $f$ for rough-bed open-channel flows is derived and discussed. The derivation procedure is based on the double averaging (in time and space) of the Navier–Stokes equation followed by repeated integration across the flow. The obtained relationship explicitly shows that the fri...

Marine renewable energy, including tidal renewable energy, is one of the less exploited sources of energy that could contribute to energy demand, while reducing greenhouse gas emissions. Amongst several proposals to build tidal range structure (TRS), a tidal lagoon has been proposed for construction in Swansea Bay, in the South West of the UK, but...

Most of the research and development on hydro-kinetic turbines has been recently focused on tidal currents where the axial flow and lift based turbine technology has generated a momentum for the performance of such turbines[1]. However, significant sources of renewable energy including riverine and shallow waters have been overlooked due to either...

Details are given of the growing worldwide interest in tidal renewable energy projects, including tidal stream devices and tidal range structures (i.e. barrages and lagoons), but the main emphasis in this chapter is on tidal range renewable energy structures. In investigating the hydro-environmental impacts of such tidal energy schemes, both for re...

Extreme floods often occur in the middle Yangtze River. The Jingjiang flood diversion zone needs to be operated during these events to protect the safety of the levees along the Jingjiang Reach. Therefore, it is important to be able to predict the potential flood risks to people and property in such an area for the purpose of flood management. In t...

Optimizing escape routes during an extreme flood event is an effective way to mitigate casualties. In this study, a model for selecting optimal escape routes in a flood-prone area has been proposed, which includes a module for predicting the two-dimensional (2D) hydrodynamics and modules for assessing the hazard degree for evacuees, calculation of...

With increasing economic benefits associated with bathing waters and increasing consumption of shellfish in internationally, water quality in coastal and estuarine waters has attracted growing public concern in recent years. Some bathing beaches have had to be closed temporarily and shellfish cultivation suspended because Faecal Indicator Organism...

There has been much interest in Marine Renewable Energy (MRE) schemes in the past decade, and across much of the globe, due to increasing interest in reducing CO2 emissions and capturing the vast untapped resources of MRE. There have been several proposals to build a number of Tidal Range Schemes (TRSs), such as tidal lagoons and barrages, around t...

Predicting the rate of Escherischia coli (E.coli) loss in a river network is one of the key conditions required in the management of bathing waters, with well verified numerical models being effective tools used to predict bathing water quality in regions with limited field data. In this study, a unique finite volume method (FVM) one-dimensional mo...

Tidal energy is one of the most predictable forms of renewable energy. Although there has been much commercial and R&D progress in tidal stream energy, tidal range is a more mature technology, with tidal range power plants having a history that extends back over 50 years. With the 2017 publication of the "Hendry Review" that examined the feasibilit...

Flood hazard maps are one of the main components of any flood risk management strategy. It is predicted that the degree of flood risk is going to significantly increase in the future due to climatic and environmental changes, and hence it is increasingly important that state-of-the-art methods are implemented for assessing human stability in floodw...

Tidal energy is one of the most predictable forms of renewable energy. Although there has been much commercial and R&D progress in tidal stream energy, tidal range is a more mature technology, with tidal range power plants having a history that extends back over 50 years. With the 2017 publication of the "Hendry Review" that examined the feasibilit...

An accurate representation of linking processes between 1-D and 2-D models is of particular importance for many flood modelling projects. This paper provides a comparison of 1-D/2-D linking methods used to simulate a hypothetical embankment failure. Comparisons were made by implementing 1-D/2-D linked models using two different 1-D/2-D linking meth...

Most urban rivers carry much natural debris, such as vehicles and trees, during extreme flood events, and these large debris, particularly vehicles, can block a local hydraulic structure such as a bridge. Such blockages usually increase the upstream water levels and cause more water to be diverted into adjacent urban areas. A scaled physical river...

The Loughor Estuary is a macro-tidal coastal basin, which is located along the Bristol Channel, in the South West of the U.K. The maximum spring tidal range in the estuary is up to 7.5 m, near the Burry Port Harbour. This estuarine region can experience severe coastal flooding during high spring tides, including extreme flooding of the intertidal s...

The potential flood inundation extent can be estimated with flood inundation models, which can differ in the level of physical and numerical modelling complexity included in the solution procedure. In recent years, several studies have highlighted the benefits of shock-capturing flood inundation models, particularly when modelling a high Froude num...

There is a desire to increase utilisation of renewable energy across the globe considering the impacts associated with fossil fuels and growing demand for electricity due to need to changes in technology and growing global population. Amongst various type of renewable energy, marine renewable energy and particularly tidal range has the advantage of...

In the current study, a model of selecting optimal escape routes in flood-prone areas is proposed based on the two-dimensional hydrodynamic module capable of simulating flood inundation processes over real terrains, including: evaluation of hazard risk to evacuees, calculation of evacuation time and selection of optimal escape routes. In the propos...

The Loughor Estuary is a macro-tidal estuarine waterbody which is located on the North of the Bristol Channel, South West of the U.K. This estuary, with a shallow inlet, traps sand and mud from Carmarthen Bay, which are discharged from upstream catchments and resuspended through the tidal cycle in the estuary. Much of the estuary dries during low t...

With the increasing awareness about climate change and rising prices of fossil fuels the demand for renewable energy is rapidly growing and so is the popularity of tidal energy production. To date only a few small scale tidal power plants are in operation, however this is about to change. The number of studies on this topic is fast increasing. Seve...

Extreme flood events, particularly in short steep river basins, are complex to model computationally and can cause: large loss of property, severe risk to people and debris (such as vehicles) to move and float, which in turn can significantly exacerbate the damage and extent of flooding. It is therefore desirable to be able to model as accurately a...

Results from a large eddy simulation of open channel flow over a rough bed with self-affine fractal properties are presented. The surface is considered to be broadly representative of rough bed forms that occur naturally in streams and rivers. The double averaging methodology is applied to enable analysis of the vertical distribution of turbulent a...

Increasing awareness of Climate Change and the rising price of fossil fuels have resulted in a rapid growth in demand for various types of renewable energy, including tidal energy. To date only a few small scale tidal schemes are in operation worldwide. One of the most attractive sites for the deployment of tidal range schemes is along the UK Brist...

In recent years health risks associated with the non-compliance of bathing water quality have received increasing worldwide attention. However, it is particularly challenging to establish the source of any non-compliance, due to the complex nature of the source of faecal indicator organisms, and the fate and delivery processes and scarcity of field...

Sedimentation and erosion can significantly affect the performance of river regulated reservoirs. In the vicinity of flow control structures, the interaction between the hydrodynamics and sediment transport often induces complex morphological processes. It is generally very challenging to accurately predict these morphological processes in real app...

Climate change is expected to result in an increase in the frequency and intensity of extreme weather events. In turn, this will result in more frequent occurrences of extreme flood events, such as flash flooding and large-scale river flooding. This being the case, there is a need for more accurate flood risk assessment schemes, particularly in are...

Due to the presence of noise and spikes in velocity measurements of turbulent flow fields, understanding the flow pattern may be seriously affected by the spurious values for zones where certain flow behaviour is not necessarily expected. In a series of laboratory experiments the velocity data recorded, using Acoustic Doppler Velocity meters (ADVs)...

In this study three-dimensional numerical models were refined to predict reactive processes in disinfection contact tanks (CTs). The methodology departs from the traditional performance assessment of contact tanks via Hydraulic Efficiency Indicators as it allows direct simulation of transport and decay of the disinfectant, inactivation of pathogens...

The feasibility and sustainable operation of tidal range energy structures has been under scrutiny over mounting concerns with regards to their hydro-environmental impacts. A comprehensive modelling approach that acknowledges the effects of marine structures on the hydro-environment has been refined to con-sider technical constraints and specificat...

The feasibility and sustainable operation of tidal lagoons and barrages has been under scrutiny over uncertainties with regards to their environmental impacts, potential interactions and energy output. A numerical modelling methodology that evaluates their effects on the hydro-environment has been refined to consider technical constraints and speci...

A methodology associated with the simulation of tidal range projects through a coastal hydrodynamic model is discussed regarding its capabilities and limitations. Particular focus is directed towards the formulations imposed for the representation of hydraulic structures and the corresponding model boundary conditions. Details of refinements are pr...

The Loughor Estuary is a macro-tidal coastal basin,which is located along the Bristol Channel, in the South West of the U.K. This estuarine region can experience severe coastal flooding during high springtides, as a result of the maximum spring tidal range of7.5 m, occurring near Burry Port. As the Loughor Estuary and the surrounding coastal waters...

Contemporary climate projections suggest that there will be an increase in the occurrence of high-intensity rainfall events in the future. These precipitation extremes are usually the main cause for the emergence of extreme flooding, such as flash flooding. Flash floods are among the most unpredictable, violent and fatal natural hazards in the worl...

The EU revised Bathing Water Directive (rBWD; 2006/7/EC) came into force in 2015, imposing a more stringent, water quality classification system for bathing waters on member states. This relates to the monitored concentration of E.coli and Intestinal enterococci (IE). Understanding the driving mechanisms behind non-compliance events is critical to...

A laboratory mock-up of a surface water groundwater system with foam blocks used to replicate a groundwater material was mounted in a tidal basin in the Hydraulics Laboratory at Cardiff University, UK. River flow in the form of a channel was generated, with an oscillating weir at the lower boundary of the system producing tides or controlled water...

Phosphorus (P) plays an important role in the eutrophication of river and marine environments. The adsorption-desorption processes of P by estuarine sediment were studied to better understand the P behaviour in the Loughor Estuary in Carmarthen Bay, UK. Three types of models were used to estimate the P adsorption isotherm for five sediment samples...

An experimental study of the performance and optimisation of a prototype novel drag-driven vertical axis tidal stream turbine is presented. The drag turbine has several unique advantages, including simple blade design, deployable in shallow waters and potential denser array spacing. Performance optimisation was conducted in the hydraulics flume at...

In this study, enhancements to the numerical representation of sluice gates and turbines were made to the hydro-environmental model Environmental Fluid Dynamics Code (EFDC), and applied to the Severn Tidal Power Group Cardiff-Weston Barrage.The extended domain of the EFDC Continental Shelf Model (CSM) allows far-field hydrodynamic impact assessment...